Surface bloch waves in periodic metamaterial structures

Subwavelength confinement and manipulation of light is of a great importance for imaging, sensing, high- resolution lithography, all-optical signal processing, as well as photonic funnels and superlenses. The diffraction limit, however, prevents such a confinement of optical radiation to the dimensions smaller than one half of the wavelength in the material. Conventional resolution-improvement techniques are based on high-index materials, and the further progress requires a design of artificial materials, such as metamaterials, with exotic (e.g. negative) refractive indices. Plasmonic metal-dielectric multilayered structures that operate as coupled subwavelength waveguides have been recently proposed for a variety of imaging systems and beam steering. This paper reports on the electromagnetic wave propagation along an interface between a metamaterial-dielectric layered structure and a homogeneous dielectric medium. Such a structure supports the propagation of surface modes in the direction parallel to the Bloch wavevector in the multilayered part of the structure. The effective material parameters are determined by a composition of the layers and so the dispersion properties of surface Bloch modes can be controlled by designing the structure itself.